Should the Cocaine Hippos Be Left Alone After All?

When we last checked in on Pablo Escobar’s hippos – the descendants of the dead drug lord’s hippopotamuses that have infiltrated Colombia’s Magdalena River basin – the government was attempting to control the invasive population by sterilizing them.

Now some ecologists are wondering if we should leave the hippos be, that the invasive species might actually be good for the local ecosystem. The idea is that megafaunae (big animals) went extinct in South America more than 10,000 years ago as humans (the original invasive species) took over. The hippos are believed to contribute to the local environments the way big beasts of the past had done.

Before Escobar's hippos invaded Colombia’s waterways, the last big herbivore here was the giant llama (Hemiauchenia paradoxa), last seen around 11,000 years ago. Long before that, there were giant capybara (Josephoartigasia monesi) the size of a small horse weighing over 2000 pounds. These creatures affected the environment in the same way Escobar’s hippos do, by grazing and pooping in and around waterways.

Hippos are considered “ecosystem engineers.” When they stomp around in shallow, muddy areas they reshape channels and ponds, which can increase habitat heterogeneity in wetlands. Their feces help disperse seeds as well as nutrients, creating niches used by native fishes,  invertebrates, and plants.

Escobar had smuggled four hippos into the country in 1981, living trophies for his private zoo near Medellín. After his cocaine empire collapsed, the hippos escaped and have been breeding in the wild ever since. The current population is about 200, a number widely expected to jump into unsustainable territory soon.

One very big problem for this population – which could be up to 1000 by as early as 2030 – is that there is no genetic diversity. Escobar had introduced only one male back in the day, so the existing animals all sprang from its loins. Without new blood, debilitating genetic mutations will almost certainly accumulate. No one is yet suggesting that Colombia import a few more hippos to the scene or experiment with artificial insemination, but that’s the direction it’s going if the pro-hippo camp gains traction.

For now, the ecologists who promote a hippo population are in the minority. The impacts, good or bad, that the invasives are having on the environment are still mostly unstudied. At some point soon, policymakers will have to decide whether to kill off these big beasts, or nurture them.

Photo credit: African Wildlife Foundation